Analgesics such as aspirin and acetaminophen have been frequently prescribed to manage post-surgical discomfort. Although their efficacies have been well established, the best method for prescribing these agents has not been carefully evaluated. Two variables will be studied in this project: a) the preoperative administration of an analgesic or placebo and b) fixed vs. demand postoperative administration of an active agent. Using a two-by-two design, eighty patients undergoing third molar extraction will be divided into four equal groups and administered acetaminophen as follows: 1) active preoperative analgesic and fixed interval postoperative analgesic, 2) placebo preoperative analgesic and fixed interval postoperative analgesic, 3) active preoperative analgesic and postoperative analgesic offered "as needed" and 4) placebo preoperative analgesic and postoperative analgesic offered "as needed". Patients will be selected from a university dental service and randomly assigned treatments. The nature of the study will be explained to the subjects and informed consent obtained. Double-blind conditions will be maintained. The preoperative analgesics will be acetaminophen 1000 mg. or an identical appearing placebo taken one half-hour before treatment. The postoperative analgesic will be acetaminophen 650 mg. provided in and envelope containing instructions for use (q.4 hrs. or for pain). A narcotic/acetaminophen back up medication will also be supplied for patients who drop out of the study. The results of this study will provide information regarding 1) the most favorable postoperative prescribing methods, 2) the value of preoperative administration of acetaminophen and 3) the sensitivity of this analgesic testing model for future use in evaluating the relative efficacy of other preoperative agents such as steroids and nonsteroidal antiinflammatory analgesics.